Folic acid supplementation during MTX therapy

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It is up to your doctor, but many physicians do not prohibit their RA patients

from taking folic acid on the same day on which they take their methotrexate

(MTX).

It's true that pharmacologically MTX is categorized as an antifolate and that

folate depletion is responsible for many of the annoying side-effects (mouth

sores, hair loss, GI upset, for example) MTX produces in rheumatoid arthritis

patients on low-dose therapy; however, although we don't really understand

exactly why MTX is effective in treating RA, it is believed that its antifolate

mechanisms are NOT those that are most important in altering the RA disease

process.

" ... Most researchers have found that folic acid levels were not related to

parameters of disease activity and concluded that methotrexate does not exert

its action in RA primarily by inhibiting dihydrofolatereductase.

(Alarcon GS, SL. Arthritis Rheum 1997 Feb;40(2):391; van Ede AE, et al.

Semin Arthritis Rheum 1998 Apr;27(5):277-292; Hunt PG, et al. J Rheumatol 1997

Nov;24(11):2230-2232; Leeb BF, et al. Clin Exp Rheumatol 1995

Jul-Aug;13(4):459-463; SL, et al. J Rheumatol 1998 Mar;25(3):441-446;

Shiroky JB. Rheum Dis Clin North Am 1997 Nov;23(4):969-680.)

Nutritional support with rheumatoid conditions: Though its use is not

universally accepted, the ability of folic acid (or folinic acid) to reduce

methotrexate toxicity in individuals being treated for rheumatoid arthritis has

made its use an important adjunct in enabling patients to tolerate methotrexate.

At this time, research supports several rationales for substantial folate

supplementation by individuals taking methotrexate for rheumatoid arthritis.

Beyond the prevention of methotrexate toxicity, the prevention or treatment of

folate deficiency and the prevention of hyperhomocysteinemia further contribute

to the therapeutic value of supplementation with high doses of folic acid.

According to the several studies cited, a daily dose of 1000-5000 mcg of folic

acid or 2.5-5 mg of folinic acid (an activated form of folic acid) can

substantially reduce the adverse effects of methotrexate without compromising

its therapeutic effect in rheumatoid patients.

( SL, et al. J Rheumatol 1998 Mar;25(3):441-446; Shiroky JB. Rheum Dis

Clin North Am 1997 Nov;23(4):969-980; Kamen B. Semin Oncol 1997 Oct;24(5 Suppl

18):S18-30-S18-39; , SL, et al. Ann Intern Med 1994;121:833-841; Ortiz Z,

et al. J Rheumatol 1998 Jan;25(1):36-43; Shiroky JB, et al. Arthrit Rheum

1993;36:795.) "

Source:

http://home.caregroup.org/clinical/altmed/interactions/Drugs/Methotrexate.htm

The American College of Rheumatology advises that 1mg per day or 7mg per week

should not lessen the effectiveness of MTX:

" Common but less serious toxicities of MTX include mucositis, mild alopecia, and

GI disturbances, which may be caused by folate depletion. These toxicities are

often treated or prevented with the use of folate supplementation, which should

be considered in all patients taking MTX. Folic acid at a dosage of 1 mg per day

or 7 mg once a week is less expensive and less complicated than the use of

folinic acid. Neither low-dose folate (1 mg per day) nor folinic acid (<=5 mg

per week) interferes with the beneficial effect of MTX . "

Source: http://www.rheumatology.org/research/guidelines/ra-drug/ra-drug.html

The following is the abstract of a research article entitled, " Methotrexate in

rheumatoid arthritis. Folate supplementation should always be given " :

http://www.lef.org/protocols/abstracts/abstr-013.html#23